「error：'xxx'未聲明的」_and_「錯誤：未使用的變量'xxx'」在同一時間，在同一個文件中

Question

我有一個非常奇怪的JNI編譯問題，不知道如何解決它...

這是一個是從靜態上下文在我的Java代碼調用的函數：

private static final Logger logger 
    = LoggerFactory.getLogger(PamHandle.class); 

private static native void initLog(final Logger logger); 

static { 
    System.loadLibrary("pam4j"); 
    initLog(logger); 
} 

頭聲明這個函數如下：

#ifndef __LOG__H__ 
#define __LOG__H__ 

#include <jni.h> 

JNIEXPORT void JNICALL Java_org_eel_kitchen_pam_PamHandle_initLog(JNIEnv *env, 
    jclass cls, jobject jlogger); 

struct javaLogger { 
    jobject logger; 
    jmethodID debugID; 
    void (*debug)(JNIEnv *env, struct javaLogger *logger, char *msg); 
}; 

extern struct javaLogger logger; 

void debug(JNIEnv *env, struct javaLogger *logger, char *msg); 

#endif /* __LOG_H__ */ 

，這是C文件：

#include "log.h" 

struct javaLogger logger; 

JNIEXPORT void JNICALL Java_org_eel_kitchen_pam_PamHandle_initLog(JNIEnv *env, 
    jclass cls, jobject jlogger) 
{ 
    jclass class = (*env)->GetObjectClass(env, jlogger); 

    logger.logger = jlogger; 
    logger.debugID = (*env)->GetMethodID(env, class, "debug", 
     "(Ljava/lang/String;)V"); 
    logger.debug = debug; 
} 

void debug(JNIEnv *env, struct javaLogger *logger, char *msg) 
{ 
    jstring jsmg = (*env)->NewStringUTF(env, (const char *)msg); 

    if (jmsg) 
     (*env)->CallVoidMethod(env, logger->logger, logger->debugID, jmsg); 
} 

但是，當我嘗試編譯它（與gcc -c -Wall -Werror -Wstrict-prototypes -Wmissing-prototypes -fPIC -g -c -I$JAVA_HOME/include -I$JAVA_HOME/include/linux log.c），這是輸出I得到：

log.c: In function ‘debug’: 
log.c:20:9: error: ‘jmsg’ undeclared (first use in this function) 
log.c:20:9: note: each undeclared identifier is reported only once for each function it appears in 
cc1: warnings being treated as errors 
log.c:18:13: error: unused variable ‘jsmg’ 

呃......我徹底驚呆了。這裏發生了什麼？ ：/我必須錯過一些非常明顯的東西，我只是不能確定什麼...

Answer 1

jmsg和jsmg是兩個不同的東西。